Guanwei Liu

Fabrication of coloured zirconia ceramics by infiltrating water debound injection moulded green body

Abstract Abstract The authors developed a new technique combining ceramic injection moulding and liquid precursor infiltration, presenting a new strategy for fabrication of coloured zirconia ceramics. The authors’ strategy includes ceramic injection moulding 3Y‐TZP powder using a water debinding binder system, debinding moulded parts in water and drying, immersing debound parts in solutions containing different colouring ions and then sintering and creating coloured zirconia ceramics. The fabricated coloured ceramic bars exhibit a core shell structure, and the thickness of the coloured shell can be tailored by adjusting immersion time and temperature. Using solutions containing different colouring ions, ceramic bars with various colours can be prepared.

Dynamics of water debinding in ceramic injection moulding

Abstract Water debinding technique for ceramic injection moulding is competitive for its high debinding rate and environmental friendliness. In this research, the relationship between debinding ratio and debinding time at different temperatures was determined. The results showed that the water debinding process could be divided into dissolution controlled stage and diffusion controlled stage. The apparent interdiffusion coefficient was defined to investigate the impact of the porosity and pores tortuosity on the diffusion. A unified equation valid for samples with different dimensions was deduced. In addition, the microstructure evolution of the green body during water debinding was characterised by formation of the connected porosity and variation of the pore size distribution.

Optimisation of compositions of PEG/PMMA binder system in ceramic injection moulding via water debinding

In this study, we have made a comprehensive investigation on the optimisation of the compositions of polyethylene glycol (PEG)/polymethyl methacrylate (PMMA) binder system for water debinding. An orthogonal test was designed, and L9(33) table was chosen to investigate the influence of the molecular weight of low molecular PEG (L-PEG), high molecular PEG (H-PEG) and the percentage of L-PEG in PEGs on flaws of the injection moulded compacts after water debinding. In addition, the ratio of PMMA content to PEG content on flaws is also investigated. Four regions were defined as high stress region, safe debinding region, low binder removal rate region and unavailable injection region respectively. It is believed that our work could provide comprehensive and convincing principles for the manufacturing of injection moulded ceramic parts via water debinding.